[officedweller]

Good question.
Would that depend on whether the new appearance diverges from the original Development Permit (and whether that permit specified colour of glass)?

The Royal Bank Tower's glass was replaced a couple of years ago and I recall reading somewhere that some people at the City was upset that they didn't replace it with clearer glass (but the HVAC, etc. were not being replaced and clearer glass would have screwed up the entire engineering for the building (think One Wall Centre)).